Why is the WinSxS folder so big? The short answer to this commonly asked question is that the component store (WinSxS folder) contains all the components that make-up Windows to allow you operate your system. These components are kept to rollback any problematic change or to repair a file that becomes corrupted.
The WinSxS folder isnâ€™t as large as it may appear at first glance because size calculations can include Windows binaries located elsewhere which makes the WinSxS folder seem larger than it really is.
This tutorial will help show you how to determine the actual size of the component store (WinSxS folder) and if you should clean it up in Windows 8.1 and Windows Server 2012 R2.